PSD. SDSL ADSL up ADSL down SHDSL POTS. Reach achieved by different xdsl technologies and Spectral efficiency.

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1 TrendCommunications Trend s xdsl Guide Quick Reference Mbit/s 2.5 PSD HDSL2 SDSL ADSL up ADSL down SHDSL POTS.5 IDSL Average Reach Achieved (km) Frequency (khz) 1100 Figure 1 Reach achieved by different xdsl technologies and Spectral efficiency. Figure 2 technology pairs Symmetric POTS Standard ADSL 1 or 2 No Yes G.992.1, G.992.2, ANSI TI HDSL 1 or 2 Yes No T1.418 IDSL 1 Yes No I.430, I.431 SDSL 1 Yes No None SHDSL 1 or 2 Yes No G Technologies comparison. AuroraPresto AuroraTango A multi-layer xdsl tester developed to provide all the features necessary for a technician to install, maintain and troubleshoot Asymmetric and Symmetrical Digital Subscriber Lines and services. Its flexible build architecture allows different modem types, as well as data interfaces and analogue test functions including TDR, DMM, ADSL, SHDSL,,, and HTTP Multi-technology Personal Test Assistant Platform for simple, fast and effective testing of ADSL, SHDSL and ISDN. It can operate in both One-button mode and Expert mode by using pre-defined test scripts and parameters. A PDA provides an intuitive graphical menu structure for testing and workflow organization. Bluetooth interface provides Tango wireless access and host independent test. AuroraForte LT2000 A powerful tool for the Physical, and layer operation of circuits. Provides E1, E3, DS1, DS3, 25, STM1/OC3 and STM4/ OC12connectivity for unparalleled multi-circuit testing, xdsl and 3G networks. Physical and BER testing is provided. Advanced features,, OAM, QoS, SVC support and Ping over, protocol decoding and remote testing. It is a hand-held tester for analogue qualification of copper pairs. It will determine their suitability for use by xdsl services prior to and during installation and maintenance. ALT2000 FlexaNetxDSL This is the right tool for A cost-effective solution that provides com- any physical qualification, monitoring or maintenance of copper pair management for Control plete loop fault subscriber loops. Extensive range of analogue large number of xdsl Centres that support a measurements for xdsl installations. Its remote make it attractive to testing capacities engineers needing a include: emulation of high-performance analyzer with precision tral offices and cus- equipment at both cen- measurements. It tomer premises, TDR, includes ultra low noise DMM, an extensive floor, spectrum analyzer, zero blindspot surements, spectrum range of analogue mea- TDR, DMM, and a collection of predefined and higher level proto- analysis,,, masks. col test.

2 V-C Access Network T-R Wide-band network Phys. level xtu-c xtu-r Phys. level Narrow-band network POTS or ISDN Transmission Network U-C2 C Splitter U-C U-R2 R Splitter U-R POTS or ISDN POTS or ISDN Terminal SM User installation network T/S SM User Network Figure 3 xdsl Reference model User DTE xtu-r xtu-c (DSLAM) Gateway NSP internal modem 2684 ADSL SLA (Internal modem) xdsl SDH/PDH 2684 SDH/PDH,,..., -25 interface 2684 F 25.6 F 25.6 ADSL xdsl SDH/PDH 2684 SDH/PDH,,...,,... bridge-type oe Ether 10-BT Bridge BT xdsl xdsl SDH/PDH PPOE Ether 2684 PHY FR... FR router-type LLC MAC 10-BT Router NAT PAT DHCP LLC MAC BT xdsl xdsl SDH/PDH 2684 SDH/PDH,,... FR Figure 4 Structure and protocols involved in the xdsl service

3 SLA Noise Return Loss Insertion Loss Longitudinal Balance Cross Talk Figure 5 ETSI masks for copper qualification.

4 ADSL Frame Fast Fast data FEC Interleaved data 250 µs Fast buffer (at the constellation encoder input) Interleaved buffer (at the constellation coder input) Fast buffer (ATU-C) fast AS0 AS1 AS2 AS3 LS0 LS1 LS2 AEX LEX FEC bytes Interleaved buffer (ATU-C) sync AS0 AS1 AS2 AS3 LS0 LS1 LS2 AEX LEX FEC bytes Fast buffer (ATU-R) Interleaved buffer (ATU-R) fast LS0 LS1 LS2 LEX FEC bytes sync LS0 LS1 LS2 LEX FEC bytes Figure 6 ADSL frame models. Flag Flag Flag Flag Flag Message FCS1 FCS1 Flag Flag Flag Flag=7Ex (optional) (optional) Identification Standard info Non-standard info SLA (optional) Type of message Version number Manufacturer Parameters Figure 7 Handshake frame format. Messages: MS, MR, CL, CLR, ACK(1), ACK(2), NAK-EF, NAK-NR, NAK-NS, NAK-CD, REQ-MS, REQ-MR, REQ-CLR. ATU-C CLR CL ATU-R ACK MS ACK t MS REQ-MR MR MS ATU-C ACK ATU-R CLR: the ATU-R sends a list with all the operation modes it accepts CL: the ATU-C responds with a list of modes it accepts ACK: the ATU-R has received the list of modes correctly MS: the ATU-R demands a operation mode ACK: the ATU-C accepts it MS: the ATU-R requires a certain operation mode REQ-MR: the ATU-C wants to select the mode and makes a request for an MR message MR: the ATU-R requires an MS operation mode MS: the ATU-R demands a certain operation mode ACK: the ATU-R accepts the request Figure 8 Handshake sessions.

5 UNI Format NNI Format byte 1 GFC VPI 1 2 VPI 2 3 VCI 3 4 PT CL HEC 5 6 Payload VPI VPI VCI PT HEC Payload CL GFC: General Flow Control VPI: Virtual Path Identifier VCI: Virtual Channel Identifier PT: Payload Type CL: Cell Loss Priority HEC: Header Error Control Figure 9 Cell format according to the Forum. User Data Packets Data Continuous stream Higher layers AAL-SAP AAL-SAP Convergence sublayer n bytes SLA CS-PDU SAR-PDU AAL Segmentation & reassembly SAR-PDU SAR-PDU SAR-PDU -SAP -SAP cells 53 bytes -PDU -PDU -PDU -PDU -PDU -PDU -PDU PL-SAP Physical Layer Figure 10 Protocol Data Unit (PDU) exchange between layers.

6 Channel 1: CID=x Channel 2: CID=y Channel 3: CID=x Channel 4: CID=x CPS-SDU CPS-SDU CPS-SDU CPS-SDU CPS-SDU CPS-SDU CPS-SDU CPS-SDU 43 bytes 18 bytes 27 bytes 32 bytes header payload 9bytes header payload header payload CPS- Packet header (3 bytes) STF, Start Field (1 byte) LI UUI CID PPT HEC CID: Channel Identifier (0 not allowed) LI: indicates the length of the CPS-SDU PPT: Type of information (data, control) UUI: Indications between end users Padding the payload of an cell with zeros if there is no information OSF SN P OSF: indicates the offset in the bytes (0-47) wher the next CPS packet starts, or padding SN: Sequence number (varies between 0 and 1) P: Parity Bit Figure 11 AAL2 format CS-PDU: SAR-PDU: n bytes 0/ bytes User data PAD UU CPI LI CRC... header PT SLA PT... PT BOM COM EOM PTI=xx0; PTI=xx0; PTI= xx1; PAD: Complements the PDU up to forming a multiple integer of. UU: allows for transparent data transmission between extremes. CPI: Aligns the PDU in 64 bits LI: Data size CRC: G(x) = x 32 + x 26 + x 23 + x 22 + x 16 + x 12 + x 11 + x 10 + x 8 +x 7 + x 5 + x 4 + x 2 + x + 1 (Calculated for the entire PDU) Figure 12 format. DSLAM (xtu-c) xtu-r Network Termination a A b B Local Loop xdsl PHY A B C a b c d xtu-r c d C xdsl link Figure 13 Multiplexing in the DSLAM.

7 Protocol encapsulation bit Flag frame structure Address Control Encapsulated Protocol packet Padding Protocol: 0001h - Padding, 0021h -, C021h - LCP C023h - PAP, C223h - CHAP FCS (cont. if 32 bit) Flag: 7Eh Address: FFh Control: 03h Flag FCS Padding Figure 14 encapsulation bytes bit SLA Version IHL Type of service Total length Identification Flags Fragment offset Time to live Protocol Header Checksum Source Address Destination Address Options (+padding) Data (variable size) Figure 15 Format BGP FTP HTTP SMTP Telnet SNMP TCP UDP ICMP OSPF Figure 16 Higher protocols.

8 Acronyms AAL Adaption Layer LI Length Indicator ACK Acknowledge LLC Logical Link Control ADSL Asymmetric Digital Subscriber Line MAC Media Access Control AEX A(S) extension byte; byte inserted in the transmitted ADSL frame structure NAT Network Address Translation ASx Any one of the simplex bearer channels (0-3) NSP Network Service Provider Asynchronous Transfer Mode OSPF Open Shortest Path First ATU-C ADSL Termination Unit Central PAD Padding ATU-R ADSL Termination Unit - Remote PAP Password Authentication Protocol BGP Border Gateway Protocol PAT Port Address Translation. BOM Begin of message PDH Plesiochronous Digital Hierarchy CHAP Challenge Handshake Authentication Protocol PDU Protocol Data Unit COM Continuation of Message POTS Plain Old Telephone Service CPI Common Part Indicator Point to Point Protocol CRC Cyclic Redundancy Check) PT Payload Type DMM Digital Multi-Meter PVC Permanent Virtual Circuit DSLAM Digital Subscriber Line Access Multiplexer RADSL Rate Adaptive Digital Subscriber Line EOM End of Message SAP Service Access Point FCS Frame Check Sequence SAR Segmentation and Reassembly FEC Forward Error Correction SDH Synchronous Digital Hierarchy FR Frame relay SDSL Symmetric Digital Subscriber Line FTP File Transfer Protocol SHDSL Symmetrical High Bit Digital subscriber Line HDSL High bit-rate Digital Subscriber Line SMTP Simple Mail Transfer Protocol HEC Header Error Control SNMP Simple Network Management Protocol HTTP Hypertext Transfer Protocol STF Start Field ICMP Internet Control Message Protocol TCP Transmission Control Protocol Internet Protocol TDR Time Domain Reflectometer ISDN Integrated Services Digital Network UDP Universal Datagram Protocol ISP Internet Service Provider UU User-to-User indication Layer 2 Tunnelling Protocol VCI Virtual Channel Identifier LCP Link Control Protocol VPI Virtual Path Identifier LEX L9S) Extension byte; byte inserted in the transmitted frame structure Distributor: Trend Communications Ltd Knaves Beech Estate Loudwater, High Wycombe Buckinghamshire HP10 9QZ UK TrendCommunications Americas: Deutschland: España: France: India: /4 UK: US: web: mail: infoline@trendcomms.com